Multiple studies indicate that participation in Behavioral Couples Therapy (BCT) is associated with robust positive outcomes for alcoholic and drug-abusing patients, in terms of reduced substance use and improved relationship functioning. Yet, community-based treatment programs rarely offer BCT to incoming eligible patients. As reported by providers and administrators in a national survey of treatment programs in the U.S., BCT was viewed as prohibitively labor intensive, due in large measure to its standard conjoint one-couple-at-a-time delivery format. Given the public policy climate that is now emphasizing not only clinical effectiveness, but also economic accountability, an intervention's efficiency (i.e., the ratio of effectiveness to program resources used to provide the service) is a critical factor in decisions by treatment programs to adopt new interventions. Although BCT has well- proven efficacy, the consensus of providers and administrators is that BCT is not efficient. To address these issues, we have studied couples group formats to deliver BCT. First, in earlier work the PI developed a 10-week BCT group with a number of conjoint sessions added before to prepare couples and afterwards to prevent relapse. While the outcomes were favorable, the added conjoint sessions and the closed group that once begun did not add additional members made it a hard sell for community agencies looking for briefer treatments and typically running ongoing groups with new members added regularly. Second, to overcome these problems, the PI and Co-PI developed a 10-session ongoing BCT group format that has rotating content and rolling admissions in which couples join the group, complete 10 sessions, and graduate. A major advantage of this ongoing group format for BCT is that it fits with the way other types of groups generally are run in substance abuse programs. It got favorable reviews in provider focus groups and showed promise in a pilot study. The pilot study with married or cohabiting male drug-abusing patients examined the efficacy of a multi- couple group therapy version of BCT (G-BCT) compared to standard conjoint BCT (S-BCT), and individual-based treatment (group and individual counseling) for the patient only. Results showed G-BCT yielded equivalent outcomeswhen compared to S-BCT, in termsof reduction in substanceuseand improved relationship adjustment, but GBCT was less costly to deliver and had superior cost-benefit and cost-effectiveness. Both G-BCT and S-BCT yielded better clinical and cost-outcomes than individual-based treatment. Also, a small-scale evaluation study indicated G-BCT was more likely to be used in community-based treatment programs than S-BCT. Thus, this proposed study will conduct a randomized clinical trial to examine the clinical effectiveness, in terms of substance use, relationship functioning, and psychosocial adjustment, of Group BCT (G-BCT) versus Standard BCT (S-BCT) for 160 alcoholic patients and their nonsubtance-abusing partners. Given the likely differences in cost of treatment delivery between the 2 interventions, we will also examine the comparative cost- benefit and cost-effectiveness of the 2 intervention packages.